Monday, May 14, 2012

Powerful Cosmic force would have destroyed Earth

http://www.messagetoeagle.com/beamatearth.php
 

A very interesting, but also frightening event took place back some years ago when satellites and observatories suddenly registered an extremely powerful cosmic force that almost destroyed Earth. The explosion, coming from the Bootes constellation was firing material directly toward Earth traveling at almost the speed of light.
 

The explosion formally named GRB 080319B was detected at 2:13 a.m. EDT on March 19, 2008. It came from the constellation of Bootes.
 

The event, called a gamma-ray burst, became bright enough for human eyes to see.
In a scientific report, Judith Racusin of Penn State University and a team of 92 coauthors state that observations across the spectrum began 30 minutes before the explosion and followed its afterglow for months.
 

The team concludes the burst's extraordinary brightness arose from a jet that shot material directly toward Earth at 99.99995 percent the speed of light. 


At the same moment Swift saw the burst, the Russian KONUS instrument on NASA's Wind satellite also sensed the gamma rays and provided a wide view of their spectral structure. A robotic wide-field optical camera called "Pi of the Sky" in Chile simultaneously captured the burst's first visible light.
The system is operated by institutions from Poland.
Within the next 15 seconds, the burst brightened enough to be visible in a dark sky to human eyes.
It briefly crested at a magnitude of 5.3 on the astronomical brightness scale.
Incredibly, the dying star was 7.5 billion light-years away.

Telescopes around the world already were studying the afterglow of another burst when GRB 080319B exploded just 10 degrees away.

TORTORA, a robotic wide-field optical camera operated in Chile with Russian-Italian collaboration, also caught the early light. TORTORA's rapid imaging provided the most detailed look yet at visible light associated with a burst's initial gamma-ray blast.






 

A powerful jet from the Bootes constellation was directed at Earth. Image credit: NASA
Immediately after the blast, Swift's UltraViolet and Optical Telescope and X-Ray Telescope indicated they were effectively blinded. Racusin initially thought something was wrong. Within minutes, however, as reports from other observers arrived, it was clear this was a special event.
Gamma-ray bursts are the universe's most luminous explosions. Most occur when massive stars run out of nuclear fuel. As a star's core collapses, it creates a black hole or neutron star that, through processes not fully understood, drive powerful gas jets outward. These jets punch through the collapsing star. As the jets shoot into space, they strike gas previously shed by the star and heat it. That generates bright afterglows.
The team believes the jet directed toward Earth contained an ultra-fast component just 0.4 of a degree across. This core resided within a slightly less energetic jet about 20 times wider.

 
Gamma-ray bursts are the Universe's most luminous explosions.
Image credit: NAS
"It's this wide jet that Swift usually sees from other bursts," Racusin explained. "Maybe every gamma-ray burst contains a narrow jet, too, but astronomers miss them because we don't see them head-on."
 

Such an alignment occurs by chance only about once a decade, so a GRB 080319B is a rare catch.
 

Could then such a gamma-ray destroy life on Earth? That depends on the nature of the burst and its location.
 

There are two type of gamma-ray bursts. 

There is a longer, brighter burst and a "short-hard" burst, which lasts less than a second but seems to give off more radiation than a longer burst.
 

If a gamma-ray happened inside the Milky Way, its effects on Earth would be much longer lasting.
 

These bursts of radiation reach the Earth's atmosphere and cause free oxygen and nitrogen atoms to bang together, and some recombine into ozone-destroying compounds called nitrous oxides.
Short gamma-rays could be caused by dense neutron stars or colliding black holes.
According to researchers, such stellar collisions might occur once every 100 million years in any given galaxy. At this rate, Earth would have been hit by several of these short-hard events over the course of its 4.5-billion-year history.
It is possible that a short gamma-ray was responsible for at least one planet-wide extinction event in the past.
We do not know with certainty what would have happened if the powerful jet from the Bootes constellation would have hit our planet, but we can be thankful it missed our planet.